Description The Mystery of the Blue Train is one of Agatha Christie.s early detective novels (a cozy mystery.no violence or gore), and where she continues to use the fictional detective Hercule Poirot as a major character. The story, set on a train bound for the French Riviera, is a true who-done-it full of mysterious characters, missing jewels, and teasing clues. Monson.s retelling of the original book captures the plot and distills it in a way that is fun for children, gently ushering them into the literary world of Christie.s mysteries. Along with the story, there are activities, games, and puzzles throughout to help with children.s engagement, and might just foster a few budding detectives.